This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Studies under this project title are focused on a variety of eukaryotic K channels that are relevant to disease states including epilepsy, arrhythmia and hypertension. Specifically, three kinds of K channels [unreadable]voltage-dependent, lipid-gated, and G-protein-gated [unreadable]have been crystallized and are in various stages of analysis. The voltage-dependent K channel is the most advanced project as we have determined multiple structures by X-ray crystallography over the past five years. Studies are currently aimed at capturing different conformations that are relevant to functional states of the protein such as 'gate open'and 'gate closed'. We have identified multiple crystal forms of the lipid-gated and G-protein-gated K channels. Diffraction is not quite sufficient for a structure determination. Thus, these proteins are in the crystal screening stage. Efforts over the next year will be to identify highly ordered crystals.